There have been developed a variety and types of injection molds for processing in-fill plastic core materials such as expandable polystyrene (EPS) and the like. All have been constructed mainly of heavy steel and large dimensional quantities of aluminum. All current predecessors have five cycles for manufacturing. The first cycle and of utmost in the current processes is pre-heating the mold and the internal walls of the steam/heat distribution chambers by purging with steam. Second is the injection of pre-expanded in-fill core material (EPS) or the like into the part chamber or mold cavity. Third cycle is pressure induction of the expansion agent of steam/heat for the second time into the steam/heat distribution chambers which is then forced through a screened material into the mold cavity for the second and final expansion of the in-fill core material thereby molding the desired part. The forth cycle, also of utmost importance is the cooling of the mold and the internal steam/heat distribution chambers and the structural wall materials in general. The importance of this cycle is critical because the part, once extracted from the press/mold part cavity, will have what is commonly known as post expansion. To preclude this from happening, the entire press/mold assembly must be lowered or cooled to a comfortable temperature range prior to extraction so as to preclude post expansion of the part. This is accomplished by current processing art with a massive flushing of the internal surfaces of the press/mold with large quantities of cold water for a given time frame or until the entire press assembly is cooled enough for the extraction of the desired part. The now instant invention accomplishes the entire full process without the need for consumption of high volumes of time and high heat ranges for a pre-heat cycle nor the need for massive amounts of cold water and the time needed for the cooling cycle mandatory in today's current processing art. The fifth cycle of the current processes would be the extraction of the manufactured part from the injection mold while the part remains dimensionally stable.